Luminaire with a rodlike lamp and lamella segment therefore

ABSTRACT

With the purpose of obtaining an axial angle of cut off for a luminaire with a rodlike lamp (1) a glare protection is arranged comprising lamellas (2), the lamellas being arranged immediately at or around the surface of the lamp to form axially spaced and radially outward from the surface extending effective surfaces.

The present invention concerns a luminaire with a rodlike lamp andmoreover of the type described in the initial phrases of the appendedclaim 1 and a lamellar segment for use in such a luminaire.

Because a rodlike lamp emits light not only in all radial directions butalso in axial direction it is aimed to design luminaries in such a waythat the light radiated is deflected under maximum utilization and insuch a way as to obtain illumination of interiors, workstations and thelike with as little glare as possible.

To deflect the radially emitted light a longitudinally extendingreflector is arranged parallel to the lamp and on that side of the lampwhich is opposite to the area to be illuminated. However, such areflector also reflects the axially emitted light without directing thisin the direction desired.

Therefore it has up till now been customary to arrange a lamellar louverat the light output side of the luminaire.

One drawback of such arrangements is that the lamellas themselvesinfluence the reflected radiation causing mislead radiation at thetopsides of the lamellas.

To avoid this the topsides of the lamellas have been blackened which,however, causes a loss of light. Complicated lamellas designed for animproved directing of the radiation have also been employed but thesehave been costly in production.

One common drawback for all these arrangements is the considerableconstructional height of the luminaire which is caused by the arrangingof lamellas at the light output side for which reason the lamellaarrangements have been left out entirely in cases where a reducedconstructional height or a simple construction was a must.

It is the aim of the invention starting from this state of art toprovide a simple protection against longitudinal glare for a luminairewith a rodlike lamp that can be manufactured at low cost and can replacethe formerly used, complicated, costly in production and bulky lamellaarrangements; further the glare protection is aimed to be to a largeextent independent of the construction of the luminaire making itpossible to provide even very flat luminaires with the longitudinalglare protection.

This is achieved with the distinctive features listed in thecharacterizing part of the appended claim 1. Thus the lamellas accordingto the invention are not arranged at a distance in front of the lamp atthe lightoutput side as being the case in the prior art. On the contrarythe lamellas are arranged adjacent to and around the surface of the lampmaking it possible to reduce the constructional height for the luminaireas a whole.

The lamellas may be mounted around the lamp suspended in their owncarrier devices. However, according to one embodiment of the inventionthe lamellas are carried by the lamp itself, the lamellas surroundingthe lamp at virtually no distance and substantially in thecircumferential direction.

The lamellas themselves are reflective, e.g., with reflective coating.The lamellas reflect the light emitted according to the reflectivecoating which may be mat or lustrous essentially without loss andwithout being translucent to the light to any substantial degree.

The distance between and the radial height of the lamellas are adaptedto ensure that a light beam emitted from the lamp in an axial plane atthe base of a lamella close to the surface of the lamp and passing justover the top of the outer edge of an adjacent lamella has just anacceptable angular direction relative to the longitudinal axis of thelamp.

Because of the arrangement of the lamellas immediately at or on the lampany other form of lamella arrangement placed at the luminaire isrendered superfluous and thus it is sufficient to provide the luminairewith a usual reflector to deflect the radially emitted radiation.

The lamellas as such are preferably manufactured from a low cost andeasily manufacture plastic material making it feasible to renew thelamella arrangement according to the invention at the occasion ofreplacing a burned out lamp replacing completely the formerly necessarydifficult and costly cleaning of lamella arrangements.

The lamellas may extend around the total circumference of the lamp butthe lamellas may also be designed to extend in full height only along apart of the circumference in case the lamp is to be mounted close to thelamp housing which may often be the case in soffit lighting.

In one embodiment of the invention the lamellas may consist ofindividual lamellas embracing the lamp entirely or partly. These annulardiscs may be slid axially onto the lamp before it is mounted and on ahorizontally installed lamp the annular discs may be slid loosely intoposition whereafter they remain in their positions. It is, however, alsopossible to apply onto the annular discs onto their circular cylindricalsurface of contact a duroplastic adhesive to be activated by the heatfrom the lamp. It is also possible to make annular discs from an elasticresilient material such as a suitable plastic material with a more orless wide slot enabling the annular discs to be pressed or snappedradially onto the lamp. In this way it is possible to provide a lampalready installed with the glare protection according to this inventionwithout removing the lamp.

Since as it has been mentioned above it is the spacing between theannular discs in connection with their radial height that directlydetermine the axial angle of light emittance, a maximum limit of thespacing between the annular discs should not be exceeded. On the otherhand this maximum permissible distance should also be utilized to thehighest possible extent to keep losses of illuminance and expense ofmaterial at a minimum.

To maintain the optimum spacing while making the fitting of the glareprotection as easy as possible it is suggested according to thisinvention to interconnect the annular discs by means of an attachedlongitudinally extending connecting member. Such a connecting member mayhave notches catching or snapping the annular discs and thereby definingthe spacing between these annular discs.

Such a longitudinally extending connecting member is preferably designedto keep its axially extending parts away from the lamp surface by thehighest possible radial spacing to present the minimum obstacle to theradiance of light. It is possible to arrange the connecting member onthe lower side of the lamp. In this case the connecting member mayextend close to the surface of the lamp and in this way it also servesas a glare protection.

It is possible initially to place the annular discs onto the lamp andthereafter to apply the connecting member. However, it is preferred inadvance to have the connecting member fitted onto, snapped onto, weldedonto or glued onto the annular discs to provide a tubelike lamellastructure that quickly and simply can be slid onto the lamp before it ismounted or fitted.

According to another embodiment of the invention a similar lamellaconstruction may also be manufactured in one piece the lamellas herebybeing constituted by half annular discs, the two halves of one annulardisc being staggered axially to simplify the manufacturing. In thiscontext the ends of the semi annular discs may be formed integrally withtwo opposite and axially extending connecting members, however one ofthese two connecting members could also be omitted in which case theends of the semi annular discs opposite the connecting member couldoverlap seen in the axial direction. In the first case it is possible tomanufacture the glare protection from a rigid material and then slidethe glare protection onto the dismantled lamp. In the second case it ispossible to manufacture the glare protection from a relatively resilientmaterial making it possible also to press the glare protection onto alamp being already mounted.

According to an alternative embodiment of the invention it may also beadvantageous to provide the lamp with at least one surrounding helicallamella forming a cylindrical helix rather than several separate annulardiscs. Such a helix can be made from a relatively stiff material andneeds after cutting out to a suitable length only to be slid over thedismounted lamp. It is, however, also possible and in respect to asimple and non-damaging packing and shipment further advantageous tomake the helically formed glare protection from a highly resilientmaterial. The turns of the helically formed glare protection will in theun-mounted state lie adjacent to each other, but after the cutting andfitting around the lamp the turns are pulled apart and the ends arefixed at the ends of the lamp either by pressing the ends into thesockets for the ends of the lamp or by a suitable ring on the lampsocket.

According to a further embodiment of the invention the lamellas as seenin a cross section along an axial plane have a profile or contouroutwardly converging into a wedge-shape and preferably with concaveflanks, the curvature of which is in the shape of a parabola or a heretoapproximated circular arc. Preferably the contour extends outwards intothe tip of lambella at an almost right angle making this tip in the formof a concave cutter with a very narrow cutting angle. By thisconfiguration an even better distribution of light is obtained.

The glare protector according to the invention can be manufactured andcomposed of individual parts but may also be manufactured to correspondto the length of the various luminaires. Further the glare protector canbe manufactured as an endless product to simplify the manufacturefurther as in this case any necessary length can be cut from a singlesupply string. In case longitudinally extending connecting members areprovided these should be flexible to make it possible to roll up thisstring.

According to the invention several interconnected lamellas may also bein the form of independent glare protection bodies beinginterconnectable in a row or just abut on each other. Such glareprotection bodies can be manufactured from a rigid material and then puttogether to fit any length of lamp. Thus it is for a given lamp diameteronly necessary to keep a single configuration of glare protection bodyto meet any practically occurring demands of installation.

The individual glare protection bodies may advantageously by their endshave holding or catching devices to ensure that consecutive glareprotection bodies at any time are fixed in the same direction. It isalso possible to make these catching devices in the form of a snaplockmaking it possible from a given number of such glare protection bodiesand in a separate operation during the fitting of a luminaire tomanufacture a glare protection of suitable size which later only has tobe slid onto the lamp.

As it has been mentioned a bright coloured plastic material withsufficient heat resistance and a lustrous reflecting surface isadvantageous and well suited for the manufacture of the glare protectionaccording to the invention. However, such a glare protection may also beprovided with a metallic reflective coating.

The lamella arrangement according to the invention may also and inparticular in connection with a rodlike lamp having a very high thermaloutput be made from metal which will also improve the cooling of thelamp. The luminaire according to the invention can in this way also bein the form of e.g. a halogene projector luminaire.

The invention further concerns a separate lamella segment for use inmaking up a glare protection for a luminaire according to the invention.Such a lamella segment generally comprises a plate or disc likereflector body, preferably with a circular outer circumference and witha central orifice for receiving or locating the rodlike lamp.

In a preferred embodiment the reflective body of the lamella segment isan essentially U-shaped disc with a slot extending from the outercircumference to the central orifice, the projecting end of at least oneof the legs of the U-shape having means for engaging it with a mountingbrace. When the width of the slot has been adapted to the outer diameterof the rodlike lamp such lamella segments may be slid into position frombelow onto an already mounted lamp either individually or in a group.During this the slot in each segment is utilized for insertion and atleast one leg but preferably both legs in the U-shape can be engagedonto a mounting brace which on one hand may serve to hold together andposition several lamella segments and on the other hand may form part ofmeans for suspending a glare protection made in this way.

In the preferred embodiment a part of the rim area of the reflectivebody is made integrally with a transverse element extending axially fromat least one side of the reflective body. Preferrably the transverseelement extends from both sides of the reflective body to provide astructure which is symmetrical around a main plane of the reflectivebody. Such transverse elements may be utilized as spacers to keep thereflective bodies to the desired relative spacing when the end face ofthe transverse element of the first reflective body abuts the nextreflective body or the end face of a similar transverse element on thenext reflective body. Further the transverse elements can advantageouslyconstitute part of arrangements to connect the lamella segments with amounting or carrying brace.

The invention will be decribed more detailed below with reference to theschematic drawings showing in:

FIG. 1 a part of a lamp with a glare protection according to theinvention,

FIGS. 2-4 cross-sections through various embodiments of the arrangementshown in FIG. 1,

FIG. 5 a further embodiment of the glare protection according to theinvention in exploded view,

FIG. 6 a fractional view partly in cross section showing a lamp withanother embodiment of the glare protection according to the invention,

FIG. 7 a fraction of a lamp fitted with applied single annular discsforming a glare protection according to the invention,

FIG. 8 an exploded view showing a preferred embodiment of a lamellasegment according to the invention with the associated mounting orcarrying braces,

FIG. 9 a planar view showing the lamella segment according to FIG. 8along the direction 9--9, and

FIG. 10 an exploded view in perspective showing the assembly of a glareprotection made from lamella segments according to FIG. 8 or 9.

In all figures the cylindrical bulb of the rodlike lamp is indicated bythe numeral 1 and lamella segments surrounding the lamp in thecircumferential direction are indicated by the numeral 2.

The preferred geometric form and dimensioning of such lamellas appearsfrom FIG. 7 in relation to the axial angle of cut off and to thediameter of the lamp 1. The symbols in FIG. 7 indicate:

α--angle of cut off

A--lamella spacing

H--radial height of lamella

B--width of lamella base

d--diameter of lamp

T--tolerance

D--outer diameter of lamella

As evident from FIG. 7 the outer diameter of the lamella D obeys thefollowing relation:

    D=d+2(H+T)

As it further appears from FIG. 7 the axial flanks of the lamellas 2 areconcavely arched, the two axial flanks converging outwardly forming atapered edge.

In a preferred embodiment the curvature is parabolic obeying thefollowing relations:

    H=A/2(1+Cos α) tan α

    B=A(1-cos α)

The curvature may also be approximated to a circular arc with radius R:##EQU1##

In the embodiment shown schematically in FIG. 7 the individual lamellas2 consist of annular discs mounted onto the lamp 1 with the prescribedrelative spacing and being pressed onto the lamp (in which case T=0) orglued onto the lamp.

However, the lamellas are preferably interconnected by means oflongitudinally extending connecting members 3.

Preferred dimensions are: ##EQU2##

In the embodiment according to FIG. 1 the lamellas 2 comprise annulardiscs divided into halves, the halves being axially staggered and thehalves being interconnected be means of a connecting member 3 extendingin the axial direction of the lamp 1. The connecting member 3 and thelamellas 2 are interconnected to form an integral glare protection bodypreferably of a length of approximately 20 cm. Such glare protectionbodies are preferably manufactured by injection moulding and have attheir ends complementary connecting members by means of which the glareprotection bodies can e connected to form an extended glare protection.

The respective lamella halves are staggered to permit an easier removalfrom the mould and a simpler construction of the injection mould.

FIGS. 2-4 show end pictures of various embodiments of glare protectivebodies.

In the embodiment in FIG. 2 two longitudinally extending connectingmembers 3 are arranged opposite each other while in the embodiment inFIGS. 3 and 4 only one longitudinally extending connecting member isarranged. One end of the lamellas 2 forming semi annular discs arefitted onto the connecting member while the other end is freelysuspended and an axial slot may be formed as can be seen in FIG. 3. Thisaxial slot can serve to fix the orientation of the glare protection orits connecting member 3 as the slot may engage a correspondingprojection. However the axial slot may also have such width that it mayspan any part of a luminaire construction extending so close to the lampthat no space is left to arrange lamellas between said luminaireconstruction and the adjacent lamp surface.

The projecting ends of the semi annular discs may, however, also overlapseen in the axial direction as shown in FIG. 4.

In FIG. 5 another embodiment of a glare protection body is shown wherebylamellas 2 are interconnected by means of a longitudinally extendingconnecting member 3. The lamellas 2 and the connecting member 3 in thisembodiment are not formed integrally but are rather being manufacturedseparately, the lamellas and/or the connecting member having notchesthat may engage each other (the arrow in FIG. 5).

In FIG. 6 is shown the end of fluorescent tube 1 whereon is fitted ahelically shaped lamella. The pitch of this helically shaped lamellacorresponds to the distance A shown in relation to FIG. 7.

Alternatively to longitudinally extending connecting members such as theconnecting member 3 in FIG. 5 each annular disc lamella 2 may also bemade integrally with a transverse element extending from the outercircumference of the lamella away from the main plane of the lamella.Such transverse elements may be provided with means for connectioneither directly to transverse elements of adjacent segments orindirectly by connection to a mounting brace. The transverse elementsmay further be utilized as spacers to define the spacing between thelamellas.

FIGS. 8 and 9 show schematically a preferred embodiment of the lamellasegment according to the invention. The lamella segment comprises anessentially plate or disc like reflective body 10, the outercircumference or contour hereof preferably being circular but possiblyalso in the shape of a parabola or the like. A central orifice or slotfor insertion receives the lamp 1 when the lamella segment is put intoplace and this orifice or slot for insertion is defined by an edge 11which should obscure the luminuous surface of the lamp to the minimumpossible extent.

The reflective body 10 is essentially U-shaped and the projecting end ofthe leg of the U-shape has been provided with transverse elements 12formed to be inserted in respective mounting braces 14 that may furtherbe adapted to hold reflectors 16. With the segments being inserted intothe braces 14 the thus assembled glare protection can be slid intoposition around the lamp 1 from below whereby e.g. resilient catchinghooks 18 may snap onto the mounting braces and thus suspend the glareprotection.

FIG. 10 illustrates in more detail the assembly of a glare protectorwith lamella segments according to the invention. The use of the crosspieces 12 as spacers to define the spacing between the lamella segmentsis especially to be seen. Further the circumference of the lamellasegments has been provided with suitable notches which can receivelongitudinally extended reflectors 20. The transverse elements 12 andthe braces 14 may have other cross sections or profiles as necessary anda suitable elastic material may be used especially to the braces 14making it possible to engage the transverse elements 12 herewith withoutit being necessary to slide the lamella segments of their transverseelements axially into the respective braces 14.

The reflective body 10 may have the form and the sizes referred to inrelation with FIG. 7. Also other elements of the embodiments accordingto FIGS. 1-7 may be incorporated in or combined with the preferredembodiment according to FIGS. 8-10.

What is claimed is:
 1. A glare protector for use with a rodlike lamp,such as a fluorescent tube, said glare protector acting in thelongitudinal direction of the lamp and comprising reflective lamellasarranged adjacent to and around the surface of said rodlike lamp andforming axially spaced reflector surfaces extending generally radiallyoutwardly from the surface of said lamp, said lamellas, when seen inprofile section along an axial plane of the lamp, being in the shape ofa narrow wedge with a tip of the wedge pointing away from the lamp andwith the wedge having concave flanks, said glare protector beingmountable to said lamp.
 2. The glare protector according to claim 1wherein said lamellas are shaped in such manner that the wedgeshaped-part does not extend right up to the surface of the lamp but isheld with a spacing therefrom by means of a thin rim or by some otherholding means arranged so as not to obscure unduly the luminous surfaceof the lamp.
 3. The glare protector according to claim 1 wherein saidlamellas are in the form of annular discs entirely or partly embracingsaid lamp.
 4. The glare protector according to claim 3 wherein saidannular discs are interconnected by means of an attached longitudinallyextending connecting member.
 5. The glare protector according to claim 1wherein said lamellas comprise at least and preferably one helix placedon the lamp and with a flat extending cross section perpendicular to theaxis of the lamp.
 6. The glare protector according to claim 1 whereinsaid lamellas comprise half annular discs which are staggered in thelongitudinal direction of the lamp and wherein at least a number oflamellas are integrally connected with at least one connecting memberextending along the lamp.
 7. The glare protector according to claim 1wherein said lamellas are suspended by the lamp and generally surroundthe lamp circumferentially, practically without distance from the lamp.8. A lamella segment for use in a glare protector according to claim 1comprising a generally plate or disc shaped refletive body preferably ofcircular circumference and with a central orifice for receiving orlocating the rodlike lamp.
 9. The lamella segment according to claim 8wherein the reflective body is a generally U-shaped disc with a slotextending from the outer circumference to the central orifice andwherein the projecting end of at least one of the legs of the U-shapeddisc has means for engagement with a mounting brace.
 10. The lamellasegment according to claim 9 wherein a part of the rim areas of thereflective body are made integrally with a transverse element extendingaxially from at least one side of the reflective body.
 11. Luminairewith a rodlike lamp such as a fluorescent tube and with a glareprotector mounted on said lamp and acting in the longitudinal directionof the lamp and comprising wedge shaped reflective lamellas arrangedalong the surface of said rodlike lamp and forming axially spacedreflector surfaces extending generally radially outward from the surfaceof said lamp and further including a glare protector acting in thetransverse direction of the lamp and comprising reflective bodiesextending longitudinally relative to the lamp and complementaryreflective bodies preferably being fitted directly onto the lamellas.12. Luminaire with a rodlike lamp such as a fluorescent tube and with aglare protector acting in the longitudinal direction of the lamp andcomprising reflective lamellas said lamellas being arranged along thesurface of said rodlike lamp and forming axially spaced reflectorsurfaces extending generally radially outward from the surface and bythe lamella profile as seen in section along an axial plane of the lampbeing in the shape of a narrow wedge the tip of which is pointing awayfrom the lamp, preferably having concave flanks and said lamellascomprising half annular discs which are staggered in the longitudinaldirection of the lamp and at least a number of lamellas being integrallyconnected with at least one connecting member extending along the lamp.13. Luminaire with a rodlike lamp such as a fluorescent tube and with aglare protector acting in the longitudinal direction of the lamp andcomprising reflective lamellas, said lamellas being arranged along thesurface of said rodlike lamp and forming axially spaced reflectorsurfaces extending generally radially outward from the surface andhaving a profile in section along an axial plane of the lamp in theshape of a narrow wedge the tip of which is pointing away from the lampand preferably having concave flanks.
 14. Luminaire with a rodlike lampsuch as a fluorescent tube and with a glare protector mounted on saidlamp and acting in the longitudinal direction of the lamp and comprisingwedge shaped reflective lamellas arranged along the surface of saidrodlike lamp and forming axially spaced reflector surfaces extendinggenerally radially outwrd from the surface of said lamp and furtherincluding a glare protector acting in the transverse direction of thelamp and comprising reflective bodies extending longitudinally relativeto the lamp.